Of course I have. But I'm not sure it's relevant to 40,000 years ago or 15,000 years ago, and the direction is exactly opposite of where the migration would have had to come from.
You're not going to be able to make a "Kon-Tiki" argument for any pollination of humans into South America. Or maybe you can.
I don't care who is right or wrong. I want to know what happened.
By the way, the horse thing has always puzzled me.
You're missing the point. Simply because humans who lived 10,000, or 40,000, or whatever years ago were primitive in comparison to us does not mean they were stupid. A raft is a simple thing to imagine, build and, over time, improve enough to make a short voyage across a narrow strait such as the Bering.
Boats powered by oars are the oldest type of boat. The oldest boat found in the archaeological record dates to 7000 years ago. Here's a link to an FR thread about the discovery. The existence of one that old and reasonably sophisticated obviously means that boat making began some unknown period of time prior to 7000 years ago. Raft making preceded boat making.
In their practical knowledge of and ability to survive in nature, ancient peoples were more rugged and advanced than modern people, accustomed as we are to machines, comfortable homes, cars, roads, and supermarkets. They could kill, butcher and preserve huge animals like mammoths with nothing more than their ingenuity and ability to work in groups.
Just as at some point in the distant past humans learned to control fire and cook their food, they surely figured out how to cross bogs, swamps, wide rivers and large lakes, then progressed to traveling along seashores in watercraft to exploit the sea's rich food sources. From crossing rivers and lakes to crossing the Bering straight on a raft is no big leap of the imagination.